Seroprevalence of hepatitis C virus in the general population of northwest Tanzania.

Abstract

Abstract. Sera from 516 participants enrolled in a population-based cross-sectional study in northwest Tanzania were tested for antibodies to hepatitis C virus (HCV). The mean age of study subjects was 29 years (range ϭ 16-49 years); 43% were men, 6% reported a history of blood transfusion, and 4% were infected with human immunodeficiency virus-1 (HIV-1). Although 53 of 516 sera (10.3%, 95% confidence interval [CI] ϭ 7.8-13.2%) were repeatedly reactive by a third-generation enzyme immunoassay (EIA-3), only 6 of the 53 were positive when tested with a thirdgeneration recombinant immunoblot assay (confirmed HCV seroprevalence ϭ 1.2%, 95% CI ϭ 0.4-2.5%). The positive predictive value of the HCV EIA-3 in this population was 18.8% (95% CI ϭ 7.0-36.4%). False positivity was not correlated with EIA-3 optical density values, age, sex, infection with HIV-1, or a history of blood transfusion, but it was marginally associated with increased serum IgG levels. We conclude that the prevalence of HCV is low in this region and that the HCV EIA-3 has a higher false-positivity rate in this population than has been reported among U.S. blood donors.Hepatitis C virus (HCV) is the major etiologic agent of post-transfusional hepatitis worldwide 1 and may also be an important cause of community acquired non-A, non-B hepatitis in certain parts of Africa. 2,3 Infection with HCV is usually asymptomatic, but may result in chronic hepatitis with progression to cirrhosis and hepatocellular carcinoma. 4,5 Assays for the detection of antibodies against HCV proteins were developed soon after the viral genome was cloned in 1989. 6 An enzyme immunoassay (EIA) represented an important advance in reducing HCV transmission through blood transfusion. Supplemental tests for detecting antibodies to HCV, such as the recombinant immunoblot assay (RIBA), have been developed to confirm reactivity detected by the EIA. 7 Studies of volunteer blood donors and general populations have shown considerable geographic variation in HCV seroprevalence:8 0.5-1.5% in western Europe, northern Europe, North America, and Australia; 1.5-2.5% in Japan and the Mediterranean region; and as high as 14% in Egypt. In sub-Saharan Africa, data on the prevalence of HCV are limited and the extent of HCV infection remains unknown in most countries. In this study, we estimated the seroprevalence of HCV in a population-based cross-sectional study in northwest Tanzania. METHODSDuring 1989 and 1990, a population-based study was conducted to estimate the prevalence of human immunodeficiency virus (HIV) in northwest Tanzania. The protocol for this study was approved by the appropriate review committees of the Tanzanian Ministry of Health and the National Cancer Institute. The study methods have been described elsewhere. 9 Briefly, the target population consisted of people living in rural, peri-urban (mainly subsistence farmers and their families), and urban areas (commercial workers). Subjects 15-49 years of age were randomly selected from household rosters supplied by the local governmen...

Reactivity of Genotype-Specific Recombinant Proteins of Human Erythrovirus B19 with Plasmas from Areas Where Genotype 1 or 3 Is Endemic

“…A high frequency of false-positive or indeterminate samples was observed in other studies of anti-HIV reactivity in samples of sub-Saharan African origin (11,18). Similar results showing high or higher false-positive rates in sub-Saharan African countries, including Ghana, were often reported with other viruses, such as hepatitis C virus (HCV) (2,29,33,35). Hypergammaglobulinemia, arising from the multiplicity of intercurrent infections occurring in sub-Saharan Africa, was discussed as a potential cause for the increased anti-HCV false-positive results in samples from this region (29,35).…”

“…Hypergammaglobulinemia, arising from the multiplicity of intercurrent infections occurring in sub-Saharan Africa, was discussed as a potential cause for the increased anti-HCV false-positive results in samples from this region (29,35). In one study, mean IgG levels for a population from Tanzania were about two times higher than those of a control U.S. population; however, no clear correlation was observed between anti-HCV EIA false positivity and the level of IgG (33). This is consistent with data observed in the current study.…”

Serological and molecular screening for viruses in blood donors from Ntcheu, Malawi: High prevalence of HIV‐1 subtype C and of markers of hepatitis B and C viruses

“…Carriage of HBV (HBsAg positive) was also high (13%) in this population and consistent with data from other highly endemic areas [Ndumbe et al, 1994;Pawlotsky et al, 1995;Oshitani et al, 1996]. The 16.5% HCV seroprevalence was high compared to the prevalence estimates reported in Western countries (0.5±2%), but consistent with data from other African countries [Kowo et al, 1995;Tess et al, 2000]. In the past, the high prevalence of HCV in Africa was sometimes attributed to non-speci®c reactivity of African sera, especially when tested by ®rst-generation ELISA.…”

Frequent Recovery and Broad Genotype 2 Diversity Characterize Hepatitis C Virus Infection in Ghana, West Africa

“…It was also suggested that false-positive results were more frequent in African populations than in blood donors from Western countries (39). In this study, this possibility was eliminated, as only samples reactive FIG.…”

“…The prevalence of HCV infection varies widely according to the location and the population studied (28). In sub-Saharan Africa, HCV prevalence has been reported to be less than 1% in southern African countries (43,45) and to range between 1.7 and 27.5% in central Africa (5,25,29) and between 1.4 and 7% in West and East Africa (1,10,36,39). The variations observed between studies appear related not only to the heterogeneity of the populations investigated but also to the methods used to detect HCV infection (36).…”